/*-------------------------------------------------------------------------
 *
 * nbtvalidate.c
 *      Opclass validator for btree.
 *
 * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *      src/backend/access/nbtree/nbtvalidate.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/amvalidate.h"
#include "access/htup_details.h"
#include "access/nbtree.h"
#include "catalog/pg_amop.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_opfamily.h"
#include "catalog/pg_type.h"
#include "utils/builtins.h"
#include "utils/regproc.h"
#include "utils/syscache.h"


/*
 * Validator for a btree opclass.
 *
 * Some of the checks done here cover the whole opfamily, and therefore are
 * redundant when checking each opclass in a family.  But they don't run long
 * enough to be much of a problem, so we accept the duplication rather than
 * complicate the amvalidate API.
 */
bool
btvalidate(Oid opclassoid)
{// #lizard forgives
    bool        result = true;
    HeapTuple    classtup;
    Form_pg_opclass classform;
    Oid            opfamilyoid;
    Oid            opcintype;
    char       *opclassname;
    HeapTuple    familytup;
    Form_pg_opfamily familyform;
    char       *opfamilyname;
    CatCList   *proclist,
               *oprlist;
    List       *grouplist;
    OpFamilyOpFuncGroup *opclassgroup;
    List       *familytypes;
    int            i;
    ListCell   *lc;

    /* Fetch opclass information */
    classtup = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclassoid));
    if (!HeapTupleIsValid(classtup))
        elog(ERROR, "cache lookup failed for operator class %u", opclassoid);
    classform = (Form_pg_opclass) GETSTRUCT(classtup);

    opfamilyoid = classform->opcfamily;
    opcintype = classform->opcintype;
    opclassname = NameStr(classform->opcname);

    /* Fetch opfamily information */
    familytup = SearchSysCache1(OPFAMILYOID, ObjectIdGetDatum(opfamilyoid));
    if (!HeapTupleIsValid(familytup))
        elog(ERROR, "cache lookup failed for operator family %u", opfamilyoid);
    familyform = (Form_pg_opfamily) GETSTRUCT(familytup);

    opfamilyname = NameStr(familyform->opfname);

    /* Fetch all operators and support functions of the opfamily */
    oprlist = SearchSysCacheList1(AMOPSTRATEGY, ObjectIdGetDatum(opfamilyoid));
    proclist = SearchSysCacheList1(AMPROCNUM, ObjectIdGetDatum(opfamilyoid));

    /* Check individual support functions */
    for (i = 0; i < proclist->n_members; i++)
    {
        HeapTuple    proctup = &proclist->members[i]->tuple;
        Form_pg_amproc procform = (Form_pg_amproc) GETSTRUCT(proctup);
        bool        ok;

        /* Check procedure numbers and function signatures */
        switch (procform->amprocnum)
        {
            case BTORDER_PROC:
                ok = check_amproc_signature(procform->amproc, INT4OID, true,
                                            2, 2, procform->amproclefttype,
                                            procform->amprocrighttype);
                break;
            case BTSORTSUPPORT_PROC:
                ok = check_amproc_signature(procform->amproc, VOIDOID, true,
                                            1, 1, INTERNALOID);
                break;
            default:
                ereport(INFO,
                        (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                         errmsg("operator family \"%s\" of access method %s contains function %s with invalid support number %d",
                                opfamilyname, "btree",
                                format_procedure(procform->amproc),
                                procform->amprocnum)));
                result = false;
                continue;        /* don't want additional message */
        }

        if (!ok)
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("operator family \"%s\" of access method %s contains function %s with wrong signature for support number %d",
                            opfamilyname, "btree",
                            format_procedure(procform->amproc),
                            procform->amprocnum)));
            result = false;
        }
    }

    /* Check individual operators */
    for (i = 0; i < oprlist->n_members; i++)
    {
        HeapTuple    oprtup = &oprlist->members[i]->tuple;
        Form_pg_amop oprform = (Form_pg_amop) GETSTRUCT(oprtup);

        /* Check that only allowed strategy numbers exist */
        if (oprform->amopstrategy < 1 ||
            oprform->amopstrategy > BTMaxStrategyNumber)
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("operator family \"%s\" of access method %s contains operator %s with invalid strategy number %d",
                            opfamilyname, "btree",
                            format_operator(oprform->amopopr),
                            oprform->amopstrategy)));
            result = false;
        }

        /* btree doesn't support ORDER BY operators */
        if (oprform->amoppurpose != AMOP_SEARCH ||
            OidIsValid(oprform->amopsortfamily))
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("operator family \"%s\" of access method %s contains invalid ORDER BY specification for operator %s",
                            opfamilyname, "btree",
                            format_operator(oprform->amopopr))));
            result = false;
        }

        /* Check operator signature --- same for all btree strategies */
        if (!check_amop_signature(oprform->amopopr, BOOLOID,
                                  oprform->amoplefttype,
                                  oprform->amoprighttype))
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("operator family \"%s\" of access method %s contains operator %s with wrong signature",
                            opfamilyname, "btree",
                            format_operator(oprform->amopopr))));
            result = false;
        }
    }

    /* Now check for inconsistent groups of operators/functions */
    grouplist = identify_opfamily_groups(oprlist, proclist);
    opclassgroup = NULL;
    familytypes = NIL;
    foreach(lc, grouplist)
    {
        OpFamilyOpFuncGroup *thisgroup = (OpFamilyOpFuncGroup *) lfirst(lc);

        /* Remember the group exactly matching the test opclass */
        if (thisgroup->lefttype == opcintype &&
            thisgroup->righttype == opcintype)
            opclassgroup = thisgroup;

        /*
         * Identify all distinct data types handled in this opfamily.  This
         * implementation is O(N^2), but there aren't likely to be enough
         * types in the family for it to matter.
         */
        familytypes = list_append_unique_oid(familytypes, thisgroup->lefttype);
        familytypes = list_append_unique_oid(familytypes, thisgroup->righttype);

        /*
         * Complain if there seems to be an incomplete set of either operators
         * or support functions for this datatype pair.  The only thing that
         * is considered optional is the sortsupport function.
         */
        if (thisgroup->operatorset !=
            ((1 << BTLessStrategyNumber) |
             (1 << BTLessEqualStrategyNumber) |
             (1 << BTEqualStrategyNumber) |
             (1 << BTGreaterEqualStrategyNumber) |
             (1 << BTGreaterStrategyNumber)))
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("operator family \"%s\" of access method %s is missing operator(s) for types %s and %s",
                            opfamilyname, "btree",
                            format_type_be(thisgroup->lefttype),
                            format_type_be(thisgroup->righttype))));
            result = false;
        }
        if ((thisgroup->functionset & (1 << BTORDER_PROC)) == 0)
        {
            ereport(INFO,
                    (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                     errmsg("operator family \"%s\" of access method %s is missing support function for types %s and %s",
                            opfamilyname, "btree",
                            format_type_be(thisgroup->lefttype),
                            format_type_be(thisgroup->righttype))));
            result = false;
        }
    }

    /* Check that the originally-named opclass is supported */
    /* (if group is there, we already checked it adequately above) */
    if (!opclassgroup)
    {
        ereport(INFO,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("operator class \"%s\" of access method %s is missing operator(s)",
                        opclassname, "btree")));
        result = false;
    }

    /*
     * Complain if the opfamily doesn't have entries for all possible
     * combinations of its supported datatypes.  While missing cross-type
     * operators are not fatal, they do limit the planner's ability to derive
     * additional qual clauses from equivalence classes, so it seems
     * reasonable to insist that all built-in btree opfamilies be complete.
     */
    if (list_length(grouplist) !=
        list_length(familytypes) * list_length(familytypes))
    {
        ereport(INFO,
                (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
                 errmsg("operator family \"%s\" of access method %s is missing cross-type operator(s)",
                        opfamilyname, "btree")));
        result = false;
    }

    ReleaseCatCacheList(proclist);
    ReleaseCatCacheList(oprlist);
    ReleaseSysCache(familytup);
    ReleaseSysCache(classtup);

    return result;
}
